A bomb went off killing two police officers and a civilian close to where the conference was taking place. The event was organised by the international Forum for Cities in Transition, but some delegates from the 12 cities involved pulled out amid security fears, while sections of the Iraqi government opposed the event.

Mr Diver said there was a real sense of deja vu in a city where checkpoints, military patrols and explosions are an everyday reality for the people.

He said: “The atmosphere was tense. We had to do a journey from where we were staying to a high-risk area, a journey of about an hour, and we had so many soldiers and police to protect us that you couldn’t help feeling a bit anxious about it.

“That kind of tension is palpable. You can feel it in the air and the security presence would remind you of here years ago, although the problems there in terms of scale and of building trust is mindblowing.